<!DOCTYPE html>
<html lang="en">
<head>
  <meta charset="UTF-8">
  <meta name="viewport" content="width=device-width, initial-scale=1.0">
  <meta http-equiv="X-UA-Compatible" content="ie=edge">
  <title>Document</title>
</head>
<body>
  
  <div id="app">
    <p id="name"></p>
  </div>
  <script src="MVue.js"></script>
  <script>

    const app = new MVue({
      data: {
        test: 'I am test',
        foo: {
          bar: 'bar'
        }
      }
    })
    app.$data.test = 'hello test'
    app.$data.foo.bar = 'oh my bar'


    var obj = {}
    Object.defineProperty(obj, 'name', {
      get: function(){
        return document.querySelector("#name").innerHTML;
      },
      set: function(val){
        document.querySelector('#name').innerHTML = val
      }
    })
    obj.name = 'hello world'
  </script>
</body>
</html>